Object recognition technology enables an object included in an image captured by a CCD camera or the like to be identified. An object recognition apparatus of one type that uses such a technology extracts an image region that contains an object from a captured image. Then, the object recognition apparatus analyzes the extracted image region and calculates feature values of the object such as a hue and a pattern. The object recognition apparatus then compares the feature values of the object with feature values of various articles registered in a storage unit and calculates the similarity of the object and the registered articles. The object recognition apparatus determines that an article with feature values having the highest similarity to the feature values of the object is the object.
Such an object recognition technology can be applied to a store accounting system (POS system), in order to identify a product to be purchased. When there are several products registered for sale that are similar to a product to be purchased, the efficiency of a process to identify the product may decrease because the apparatus or the user thereof needs to determine the product to be purchased from many candidates. In addition, a store may not sell all of the similar products that are registered for sale. It would be desirable to decrease the number of candidates as much as possible to efficiently identify the product to be purchased.